Color displays are known to be used for applications such as Helmet Mounted Displays (HMDs). Achieving a high brightness color display with needed contrast for an HMD during the day may be difficult. Bright green displays have been proven in many existing HMDs and can be achieved with technologies which include Active Matrix Liquid Crystal Display (AMLCD), Organic Light Emitting Diode (OLED) and Liquid Crystal on Silicon (LCOS) technologies. For example, AMLCD displays that are backlit with green LEDs are known. These green LEDs are extremely efficient and achieve the needed brightness with between 1 and 3 watts. Since the backlight is green, no color filters are required. The transmission for such displays, however, is 15%, and therefore the backlight needs to be above 17,000 ftL to achieve at least 2500 ftL at the face of the display. A full color AMLCD would require filters that would reduce the transmission to between 3 and 5%. This increases the backlight requirements for green to 50,000 ftL for full color.
LCOS displays are also known. LCOS displays are reflective and provide efficiency for color displays. With a reflective efficiency of 70% and fill factor of 90%, a bright green LCOS display for day is achievable. Full color displays for LCOS are achieved by full field sequential lighting of the display with red, green and blue high brightness LEDs or lasers. This provides a high resolution color display, but must be refreshed at a minimum of 180 Hz and synced with alternating three color lighting.